This invention relates to window operators and in particular to window operators for use in awning-type windows, particularly those of metal construction such as might be used in recreational vehicles, mobile homes and the like. The invention may also be used for casement type windows as well.
The prior art has provided numerous forms of closure operators for awning windows and the like. One such prior art arrangement has a twin arm operator located in a fixed position in the center of the fixed frame at the bottom of the awning. Since the operator is fixed, the arms are not able to move upwardly or downwardly to accommodate the arcuate path of travel of the awning window as it moves between the open and closed positions; such fixed arms can only move outwardly in a generally horizontal plane. In order to accommodate the arcuate movement of the awning window, the rigid twin arms have riveted to them flexible steel extensions with a small wheel on each end which runs in a track which is fastened to the bottom frame of the awning. A problem with these flex steel extensions on the twin arms is that the amount of flexing is relatively limited and this only allows the awning to open to a maximum of about 20.degree. which has the effect of blocking the direct breeze from entering. Since the flexing movement of the steel extensions is limited, awning windows of substantial vertical dimension must be used in order to achieve a relatively shallow or flat arc of movement of the lower edge of the awning. Unfortunately, this arrangement does not permit the awning to be lifted up sufficiently to let direct breezes enter through the window. It would therefore be most desirable to provide a system enabling even relatively short awning windows to be lifted high, i.e. to open up to a very large angle to let the breezes in thereby to provide maximum ventilation. In summary, the twin arm operating arrangement previously known with the flex steel extensions can only be used with awning windows of a substantial height (vertical dimension) and yet at the same time the ventilating capability of such windows is very limited since the low degree of opening angle prevents direct breezes from entering.
Another form of window closure, which also has an operator with a handle for opening and closing located in the center at the bottom of the window frame, includes twin operating arms with linkage extensions of about equal length which pivot at a riveted joint and close in a scissor-like fashion during awning closure while straightening out while the awning is being opened. The linkage extensions are fastened to a pivot point which, in turn is secured centrally at the bottom of the awning frame. One notable drawback of this arrangement is that virtually all mechanical advantage is lost when the awning reaches the closed position. This is due to the fact that when the main arms are in the closed position the linkage extensions are almost parallel to the main arms. Hence, the closing force necessary as to achieve a good seal is difficult, if not impossible, to achieve. Furthermore, there may be a security problem since an intruder may find it relatively easy to pry open the window from the outside with breakage or bending of the linkage mechanisms occurring as a result of the very high stresses involved.
Another window operator previously known incorporates a tubular member running across the bottom of the awning and which is fastened to it on both ends. Eyelets riveted (so that they can pivot) to the ends of the twin arms of the operator slide along the round tube, inwardly toward each other for opening and outwardly away from one another during closure of the awning. Again, the operator is fixed. The flexing of the twin arms is very limited, as they have no flex steel extensions, thereby putting great stress on the operator even when only partially extended. Consequently, this operator can only be used with a high awning window and even then it provides for only a limited ventilation effect, due to the low arc of the awning, thereby preventing the direct breeze from entering.
Various prior art systems have disadvantages in that they are clearly visible either from the outside or the inside; certain of them interfere with screens and/or curtains. Certain systems, owing to play in the linkages caused by manufacturing and installation tolerances, make it practically impossible to synchronize both sides of the sets of linkage pieces with one another thus making it impossible to equalize the pressure or force supplied to both sides of the awning window thereby to effect a good tight closure. Other systems have the operating knob or crank in a position such that the window curtain must be moved every time one needs to turn the knob or crank for opening or closing of the awning.